RX7Club.com - Mazda RX7 Forum - Function over form: Stock automatic to Semi-pport, A2W, GTX42R, T56 Magnum, 40+psi!

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Function over form: Stock automatic to Semi-pport, A2W, GTX42R, T56 Magnum, 40+psi!

I bought my first RX-7 on Craigslist and it was a piece of crap. It was an automatic ‘87 GXL FC that just didn’t have enough power. I figured I would solve the problem by replacing the motor with a FD REW motor. Being as naïve as I was, I asked around to see who I could get the motor from. One of my buddies knew a guy who had a few RX-7’s laying around so I inquired about buying a 13B-REW from him.

As I’m talking to this guy and looking at his stockpile of motors he shows me one in a pretty molested/beat up ’93 Montego Blue FD. It’s sitting behind his barn, halfway covered with a car cover and it looks like it has been forgotten and left to rot. It’s by far the worst condition FD I’ve ever seen but he says the motor is a reman and has pretty low mileage but has no way to verify it.

We open the hood up and it looks like the engine has caught fire. It looks completely ruined, it’s dirty, stinks, has stuff growing on it, and somewhat melted from what I presume was the first engine. So we begin talking about the car just for kicks. He tells me that the car has no starter, needs coils, and has been sitting for about 2 years. He tells me he doesn't even know if the engine runs because he bought the car to put a 3 rotor in and has since acquired too many cars to worry about this one (must be nice). I asked him what he would want for the car since it is sitting mud left to rust away and is horribly dirty(something I can't stand to see). We start to negotiate and finally he tells me he'll take what he's got in it, $6000. So we strike a deal.

So I got my dream car for what I expected to spend on the engine swap alone. It was an automatic, had no radio, ripped tan leather seats, ruined interior tan panels, broken driver's side door handle, stained carpets, faded steering wheel and the list goes on and on. The exterior had a dent/scratch on the passenger side rear quarter that goes from the door to the rear bumper. The front bumper and hood have a mark from a tow truck hook riding across the front end. The driver's side door is dented beyond repair, and NOTHING WORKS. The car doesn’t even start. I didn’t care one bit; I had my damn dream car.

So the healing begins. We tow the car out of the mud with a tractor and I start wrenching. First things first, put a starter on her, but where is the starter? I search for about two hours before I find it hiding in his barn without any bolts or anything. I manage to find something that will hold the starter on there for the time being until I can find the proper size bolts. I spend about 5 hours putting the starter on and hooking random other hoses and wires back up under the car in the dirt. I then had to take a break since it was getting dark.

I got up early the next day and head to work on the car. I find a new coil pack in his garage and take it out to the car and start wrenching the UIM off. I see why it’s called a rat’s nest. I find several disconnected hoses and wires. I get the UIM off after a mind boggling 3 hours and put the coils on. I get the UIM back on and check all the fluids. Looks like the coolant is non-existent, the oil is from ancient Rome, and the belts are destroyed. Hell, one of the belts is actually three different bands that came apart. I venture off to AutoZone and find out that they carry NOTHING for rotaries, I’m flabbergasted. I manage to find a belt that looks like it will work, some coolant and an oil change. I change the fluids out and pop the belts on.

I jump in like a kid who just got a new bike. I twist the key like a madman would and NOTHING. The battery is dead, go figure right? I should have checked it… So I grab the charger and hope that the damn battery will hold a charge. I start cranking about an hour later and she fires right up but dies almost immediately. What the hell? I crank it again and she fires up and runs for another second and dies again. So I start checking everything and realized the plugs were probably fouled out pretty bad after 2 years. I change the plugs out and give it another shot. She fires right up like a champion, jumps right up to 2k and smokes like she’s been in prison for 15 years. I damn near break into tears hearing the exhaust purr and the engine run so smoothly. I sure got lucky.

I let her run for about 30 minutes. I’m checking the hoses, the fluids, the gauges, and the wiring. I’m running around like a madman would, one who has just awoken Frankenstein. SHES ALIVE!! I decide it’s time to see what she does in a road test, seeing as I bought a car that I didn't know anything about. I pull her around slowly and finally hit the pavement. I give her a little gas and start to hear the primary turbo whistle. It shoots chills down my spine, my first turbocharged vehicle! I slowly inch into the throttle a little bit more and she backfires, stutters and almost shuts off. I think to myself, what have I done? She’s running so smooth and this?

I spent the next THREE MONTHS replacing vacuum lines, hoses, wires, fuses, filters, EVERYTHING and anything under the hood. Still nothing, she’s still a backfiring twin turbo gas guzzler. I finally stumbled upon a bad relay and found that it was my fuel pump speed relay. This relay basically shoots the fuel pump into high gear. I had no reason to suspect this would solve my problems but tried it anyway.
Out of curiosity I take her out for a spin and push the gas down to expect a backfire at 7lbs but I get nothing. She climbs up to 10lbs around 2400 rpms. I thought my gauge was broken so I floored it. She downshifted into first right into the powerband and both tires broke loose. I held on like I was being baptized. Ofcourse this just happened to be next to an elementary baseball field full of kids. She screamed by full boost and had me in love.

Over the years, I’ve spent well into the thousands of hours working on her. So this is what a project car feels like? I’m addicted.

Fast forward a few years: I've cleaned the paint to her utmost ability. I've replaced the intake system, the intercooler, the pipes, the battery, the vacuum lines (twice), the FF, the coolant lines, the driver side door handle, the drivers side window switches, the CD player, the front door panel speakers, added boost and water temp gauges, installed a complete Bilstein strut/spring system, added a Greddy Profec B II to limit boost spikes (first to buy to LOWER boost), and so many other things slowly replaced. I finished swapping in a 5spd and adding on a new set of twins. I am going to remove the air pump, the rats nest, upgrade the fuel system, and tune the PFC for more.

I feel that I am part of the car with all of the time I have put into her. I have always loved RX-7's but since I've owned this car, there is no doubt in my mind that I will always have a RX-7 in the driveway.

Fast forward to now: I’ve done so much work I can’t even remember all of the parts I’ve put on the car. I guess that’s where this build thread came into existence. Doing my best to put it into order!

FYI: This text is from a build thread I made on another forum several years ago. It made me laugh when I found it, so I just copied it and posted it here. I was probably about 20, so try not to judge too much. I feel like it captures my joy much better than if I were to rewrite it. Enjoy!

Taking a break for a bit, still about a hundred more pictures to go.

Great way to start the thread with your story! Fantastic!

Cool story, nice save on the FD.

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More turbo woes, these twins are picky and I'm not getting very lucky.

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So about 4k miles after the trans swap, the motor lets go. It has a bad knocking sound that is just about as audible as rod knock in a piston motor.
http://www.youtube.com/v/k4quhEJCwy8

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The new crate motor! I thought about rebuilding my motor but got a really good deal on this motor instead.

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So shiny!

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Couldn't get the rear counterweight off, so I tried to pry it off and it cracked. Use a puller next time.

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Starting the build up. It was around 20F outside so I did it in the living room.

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The living room is a mess, my old roommate was helping out.

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Already looks old haha. Theres a lot of stuff on these engines.

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Ready to go!

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I decided since I had the engine out I should go ahead and do a wiring harness swap for the 5 speed conversion as well. I never liked not being able to plug and play some of the sensors and connectors on the automatic harnesses.

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What have I got into?

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A little snow

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Did a full 3 stage buff on the paint job to attempt to get some of the luster back. Unforunately it didn't help much after about a week as the paint is shot.

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Starting to acquire some more parts for more power! Looking into swapping to a single turbo.

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A couple of weeks later, the inevitable comes. The wiring on my HKS harness splits and crosses the coils firing order around. Not even Aux Injection could have saved the motor. It kills the compression on the front rotor and I limp it home.

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So I start ripping it apart in my buddy's garage. Looking into getting it rebuilt.

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Yank the motor out to take a look in the exhaust ports. I must have forgot about the other transmission swap I did before. I had a Spec clutch but got rid of it when I swapped transmissions out. The Spec clutch was a great clutch but just not for me. I got a ACT Xtreme with a MM friction material.

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Left the trans in it this time around.

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Looks like the a seal chipped the rotor face. Haven't cracked it open yet to see what actually happened.

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My buddy ends up totaling his FD and asks if I want to buy his setup. I ask him if he wants to put it into another chassis and he declines. He's been thinking about selling the car for awhile and wants to move onto something else. So we negotiate on a price and I end up with a streetported motor setup for a single turbo. So I sell off some of my parts and combine the best of both cars.

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I also bought his GT35R setup. The sch 40 stainless manifold cracked in the wreck and had to be repaired.

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Everyone has one of these pictures! :)

I was running on a PFC and never really liked how it worked. It always felt like a modified stock ECU with a commander and a rigged up datalogit. Don't get me wrong, it works amazingly well but I wanted more. So I picked up the AEM EMS setup and ran with it. Not many people run it here but it's a great setup after you get all the quirks taken care of. It has a lot more customization and picks up a lot more data/sec than the PFC does.

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A picture of the cracked manifold.

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Nothing a few passes can't fix.

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Starting to look menacing!

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Lowering the motor back into the car.

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Had to rig up a pipe to make it run.

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So the motor lasted about a week before the rear rotor corner seal cracked. The motor dropped a pretty noticeable amount of power. So I pulled it back out and sent it off for a rebuild at Bruce Turrentine's shop. Slipped a fresh pair of RA Super Seals in it with OEM springs and a few other goodies.

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Starting to get it back together. Most of my friends are starting to think I'm crazy for not giving up yet. They just don't understand what it's like haha.

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Piece by piece, gasket by gasket I go through the motor. I'm making sure theres nothing that can fail this time around. I add a few little things this time around.

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I finally get it all back together and have a new intercooler pipe welded up. Starting to look a lot more like my style.

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So I've got it settled out pretty well and a local guy asks if I want to run it against a friend of his. Turns out his friend is known as "Boostdoctor" online and has quite a reputation. I figured what the hell, let's see what his car has. The car turns out to have a boosted LS1 running on E85 and it's built to run. The Caprice is primer gray, has stock wheels (with drag slicks on the back), a built rear-end and a TH400 trans in it. He kept the stock column shifter, stock gauge panel, and bench seat. You literally can't tell the car is modified by looking at it. I obviously lost to this car but did get to keep up with the GTO pretty well. The second race around I was dead even with the Caprice but then his motor let go so it was pretty obvious he was down on power through that run. This is about the best video I have:

http://i67.photobucket.com/albums/h2...80974206_n.jpg
I went the drag strip and ended up blowing out the turbo to manifold gasket. The gasket problem also turned out to be a problem with the turbo coming loose on it's own periodically. I tried using Nord-locks, lock washer, thread locker, etc but nothing worked. I finally picked up a set of Stage-8 locking nuts and haven't had a problem since.

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Got the keg kart running at work haha. Bored out Briggs 5HP cart with a modified carb and broken throttle linkage. Always stuck at full-throttle so it was about as dangerous as it can get. Still a blast to ride.

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A little DGRR fun in 2011.

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Picked up some Mickey Thompson ET Streets and dropped by the track. The car had more traction but that led to more problems. I cracked the PPF!

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A few welds.

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I decided to seam weld the rear portion a little.

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Playing around on the street with ET streets and the tire blows out at 70mph. I contacted Mickey Thompson about a warranty repair and they declined. Didn't get a very good taste in my mouth but I decided to let it go.

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Split right in half.

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So I picked up a set of ET streets bias ply. 26x11.5x16

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Turns out they're almost identical in size as the 255/50/16's. Good thing I measured!

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It's a tight fit but it works!

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Had to modify the exhaust so it was further off the ground.

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I heard an exhaust leak and thought the turbo came loose again. Turns out the manifold cracked all the way around the T3 flange and the wastegate runner again!

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I don't know how it was still attached!

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Gusseted the runner this time around.

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Put a thick bead on the flange with a little more flexible material.

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Car was looking pretty good after a quick wash/polish.

Awesome story and props for not giving up on the car. It looks great!

Thanks everyone for the props, it's been a long journey but definitely a good one.

When I get the car back I'll take some more pictures of the suspension work I've done too.

Mental note to post about the GT35R blowing up and the differential swap. The turbo started squeaking and getting louder and louder. It was approaching the 7 year mark of use so I knew it would probably die soon but I waited for the inevitable. So one day I'm pulling out of my complex and it finally let go. I knew for certain it was a catastrophic failure because it hit the exhaust housing hard, real damn hard. The sound was akin to nails on a chalkboard but on a much higher decibel level. I was lucky that I could u-turn and pull back into my garage because I don't know how the turbo or my ears would have done if I had to go much further.

As I was pulling the turbo apart to see the damage, I could see some serious damage on the exhaust turbine. At first I thought it was related to the bearing failure but it turns out that the turbo had ate some seals on a previous build. I never had any problems out of the turbo but I guess I should have checked it prior to buying the kit. Either way I send the turbo out to have it inspected to see if it's eligible for a core to buy a new cartridge. I thought about upgrading to a bigger turbo or a billet wheel but the $500 price tag on a standard cartridge was hard to pass up. Maybe down the road I'll swap to a divided T4 Precision 6765 or even a 3 rotor but not anytime soon.

You'd think the new cartridge would have made a big different in spool with the damaged exhaust turbine but there is absolutely no difference. It may have been slightly out of balance which could have caused a early failure but there's no way to be certain. I've talked to a few performance shops about it and they all seem to think I did pretty good. They all seem to think high performance turbos only last around 10-20k miles and since this one was approaching 25k, I can't complain.

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Blown turbo with exhaust turbine damage. The c-clip for the front cover is a pita to remove and reinstall. Definitely plan ahead if you plan on doing a CHRA replacement.

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Shiny new turbo!

The first three are just progress pics, the last one is how many times the hood was painted. I got the hood from a friends car a few months ago thinking it was in good shape.

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Wow. I thought I had a rough time with my car. This thread has made me quit my bitching.

I did a similar manual-auto swap and I also changed out the harnesses, with one major glitch.

I have changed out the engine, dash and ring harnesses since they are different on the manual. From what I can tell, early model cars had three sensors on the coolant tank including a coolant thermosensor. Later model cars had only two sensors. I have an early 94 car that had 3 sensors, but the maunual engine harness had conectors for only two sensors. The used manual ecu is expecting input from that missing sensor, so the car is running rich and the fans don't work. If anyone knows the pin assingnments for this, I could wire it direct, but my repair manual doesn't show a pin assignment, even though the sensor is addressed in the cooling section. What a mess!

Quote:

Originally Posted by gegger (Post 11299587)

Have you checked the 94 wiring manual? It's got full pin-outs for every connector on our cars.

Aron, Yes, I checked the manual, but my 94 repair manual doesn't have an assignment for the third sensor. It has assigment for the two wire sensor in the back (coolant temperature sensor) and the low coolant level senorin the front, but it does not list an assignment for the third sensor, which is another one-wire sensor in the front identified only in the cooling sytem section of the repair manal as the "water thermosensor".

Very interesting build thread so far, I admire your persistence lol

are you painting the car the same color? Can't wait to see the 99 spec conversion come to life, I have decided that's something I want to do as well eventually.

Good stuff, and great perseverance!

There's one pic with the front wheels off, in that pic the car has FC front brake calipers. Not sure if that's still the case, just FYI :).

Don't know if I talked with you at DGRR 2011, if not hopefully I'll see you in 2013!

Dale